Boiler



J. H. LAWRENCE BOILER :s sheets-sheet .1l

Filed March 21, 1936 I N VE N TOR. LJ'H/v ffL/z weg-NGE,

ATTORNEYS ug. 15, 1939. J, LAWRENCE 2,169,843

BOILER Filed March 21, 195e :s sheets-sheet 2 I N VE N TOR. ./H/v HLA Weg/VCE.

ATTORNEYS A08- 15k. 1939. l J. H. LAWRENCE 2,169,843

, INVENTOR.` SHNHLA Wma/V05.

MYW/ M4 ATTORNEYS llil Patented Aug. 15, 11939 UNITED ori-ies Bomen Application March 21, 1936, Serial No. 70,013

4 Claims.

The invention aims to provide a boiler in which a comparatively large area of heating surface is provided in a compact structure. It is thus particularly adapted to boilers for household use where economy of space is important. By the provision of a large heating surface it also serves to heat the water or generate steam quickly and at a. high rate.

The accompanying drawings illustrate an em bodiment of the invention.

Fig. l is a longitudinal section through a boiler and furnace. Fig. 2 is a horizontal section through the water chamber and heating and circulating pipes. Fig. 3 is a Vertical section approximately on the line 33 of Fig. 2.

The main casing comprises a cylindrical shell I with a dome 2. In the lower part of the casing is a smaller shell 3 constituting the furnace, adapted to take the usual grate or oil or gas burners and attachments. A door Il admits the fuel or the burners. The heating gases pass out through openings 5 at the opposite side. Between the outer casing l and the furnace wall 3 is a downwardly extending leg or space t communicating with the langer water chamber 'I above the dome 8 of the furnace.

The door 4 and exits 5 from the furnace are in the form of tubesv spanning the water leg 5. The water chamber is provided with any usual or suitable couplings and other details for the feeding and the circulating attachments.

The present invention is directed particularly to the heating of the water. For this purpose there is a supplementary chamber 9 in a casing I6 fixed on the back of the main casing I, communicating at its lower end with the furnace through the exit tubes 5 and having an opening I I at the top leading to the smoke pipe or chimney. rWithin the chamber 9 are sections of boiler tubing I2 which in plan are concentric: or parallel to the back wall of the casing, as in Fig. 2, and which in elevation are inclined as in Fig. 3. The ends of the tubes I2 are bent inward and enter the casing I so as to communicate with the main water chamber. The hot gases traveling overl these tub-es heat the water therein causing it to flow into the main water chamber at the higher ends of the tubes and from the water chamber into the tubes at their lower ends thus heating and circulating the water in the main chamber.

The heating surface is greatly increased by means of projections I3 welded to the portions of the tubes within the chamber 9. These projections are in the form. of small ns extending a considerable distance radially outward from the tubes andI having comparatively small ends welded tothe tubes separately; thus avoiding the strains in welding and in use which would occui1 with welded joints of any considerable length.

By providing numerous projections separately welded but closely spaced to e-ach other along the lengths of the tube and also circumferentially, and extending a considerable distance radially outward from the tube, a very great and most effective heating surface is provided beyond w that which could conveniently be secured by the ordinary method of passing the heating gases through tubes within the water chamber. We have, in, fact, with the approximate compactness of the ordinary fire tube boiler the greater heati ing effect obtainable in water tube boilers. There being no lire tubes through the main water chamber l, the dimensions of this chamber may be made considerably smaller for a given volume of water, thus compensating in a measure for the 2O extra space taken by the casing I0.

In the case illustrated, if the tubes I2 are assumed to be of two inch diameter, then for every lineal foot orf these finned tubes we can Secure 555 square inches of heating surface, taking the projections to be as illustrated. Four feet of such tubing, or say three 18 inch lengths thereof (4l/2 feet) will provide a heating area equal to that of an ordinary sized house heating boiler. Thus the completed boiler is compact notwithstanding the supplementary chamber.

The supplementary casing with its finned tubes therein may be manufactured as a separate unit adapted to t against the outside of the: boiler casing and to be welded thereto as shown, it being necessary only to provide holes in the outer casing I of the boiler for the ends of the tube sections I2, the shell I of the main casing constituting one wall oi the supplementary chamber. The two chambers 'I and 9 are thus closely coupled `and are also united in operation, the heat units being applied almost wholly in the part S where they are most effective and being there applied to cause a high heating as Well as a forceful circulation of the water in the two chambers.

Where insulation is to be used it may be applied after the supplementary casing is fixed on to the main casing. For example, Fig. 2 shows the completed structure enclosed in an insulating compound I4 held in place by a steel jacket I5; 50 the insulation being continuous around the assembled structure, though partly broken away in the drawings.

'Ihe steam or hot water outlet pipe will be attached to the coupling I6, the return pipe for condensed steam or feed water will be attached to the coupling l1. The small tubes I8 and i9 are for application of pressure gauge, pressure regulator and other usual attachments. The boiler generally is of a standard type similar to that described in a coi-pending application of Henry S. Holmes, Ser. No. 68,605; filed March 13, 1936; the supplementary heating chamber with water circulating tubes being substituted for the internal fire tubes which pass back and forth through the main water chamber in said Holmes application.

Various modifications may be made by those skilled in the art without departing from the invention as defined in the appended claims.

What I claim is:

1. A boiler having a furnace, a main water carrying chamber above the furnace, a relatively narrow heating chamber extending upwardly adjacent a portion of the outer surface of said water carrying chamber for the upward passage of gases therethrough, and a number of water heating tubes in said chamber transverse to the passage of gases' therethrough and approximately parallel to the surface of said water carrying chamber, and connected to said water carrying chamber at their opposite ends at different levels.

2. A boiler having a. furnace, a main water carrying chamber above the furnace, a heating chamber extending upwardly from said furnace alongside an outer wall of said water chamber for the upward passage of gases therethrough, a vertical series of water heating tubes transverse to the passage of gases through said passage and approximately parallel to the surface of said Water carrying chamber, each tube being connected at its opposite ends to said water chamber at different levels, and each tube being provided with fins projecting outwardly in planes at right angles to the center line of their respective tubes, said projections being narrow plates extending outwardly from their respective tubes at angles of approximately 45 to the horizontal and extending through the spaces between said tubes and the walls of said passage.

3. A boiler having a furnace, a main Water carrying chamber above the furnace, a relatively narrow heating chamber extending upwardly adjacent a portion of the outer surface of said water carrying chamber for the upward passage of gases therethrough, and a number of water heating tubes in said chamber transverse to the passage of gases therethrough and approximately parallel to the surface of said water chamber and connected to said water carrying chamber at their opposite ends at different levels, said tubes having fins projecting outwardly at planes intersecting their respective center lines in the spaces between said tubes.

4. A boiler having a furnace, a main water carrying chamber above the furnace, a heating chamber through which the hot gases pass directly from the furnace, water ltubes in said heating chamber closely spaced from and approximately paralleling the surface of said main chamber, having their opposite ends above the furnace and communicating with the main chamber and being highly heated by the passage of such gases so as to cause the water to circulate forcefully through said chamber and said tubes, the casing of the main chamber having a downward extension around the furnace wall and spaced away therefrom so as to form a water leg communicating with the main water chamber, a feed water connection at the bottom of said water leg, and a steam or hot water outlet pipe at the top of the main chamber.

JOHN H. LAWRENCE. 

